(1) Field of the Invention
This invention relates to railway systems and, more particularly, to electrical connectivity for railway systems molded of conductive loaded resin-based materials comprising micron conductive powders, micron conductive fibers, or a combination thereof, substantially homogenized within a base resin when molded. This manufacturing process yields a conductive part or material usable within the EMF, thermal, acoustic, or electronic spectrum(s).
(2) Description of the Prior Art
Mass transit railway systems are frequently powered by electric motors. In these systems, electrical power is generated from a power station and is then supplied to the train through overhead wires or through power rails on the track. This electrical power may be direct current (DC) or alternating current (AC). An electric motor, or set of motors, converts the supplied electrical power into mechanical torque which is applied to the wheels of the train. The electrical connectivity between the train and the railway power supply typically comprises several components. Among these components are an overhead wiring network, often called a catenary, a train-to-overhead wiring contacting device, typically called a pantograph, a power and/or grounding rail, typically called the third rail, and a train-to-rail contacting device, typically called a shoe. In a typical electric railway system, the above components are constructed from metals such as steel, copper, or aluminum. The prior art systems provide circuit conductivity but include several disadvantages. First, metal wires, rails, and contact devices are susceptible to oxidation and other corrosion due to exposure to weather or due to electrolytic events. This oxidation and corrosion structurally weakens these devices and substantially increases electrical resistance, power loss, and maintenance costs. Second, the weight of metal wires, rails, and contact devices create several concerns. Heavy overhead wires require heavy support poles that increase railway construction costs. Similarly, heavy metal conductive rails require heavier support bridges and overpasses. Heavy contact devices, such as metal pantographs and shoes, directly increase the weight of the train and result in reduced energy efficiency and/or slower operating speeds. It is an important object of the present invention to provide railway power systems comprising overhead wiring, power rails, and/or contact devices exhibiting improved oxidation/corrosion performance and reduced weight among other advantages.
Several prior art inventions relate to railway systems. U.S. Pat. No. 4,363,940 to Bertelsbeck teaches an electrically driven rail or track bound vehicle with a height and width adjustable current collector for gathering the power supply from an overhead wire. U.S. Pat. No. 5,584,369 to Makino et al teaches a high speed low noise current collector for a railway vehicle that utilizes aluminum as the conductive element for electrical contact to the overhead wire. U.S. Pat. No. 4,900,992 to Sekizawa et al teaches an apparatus and method for controlling an electric car that utilizes a third inner rail to supply the power for the linear induction motor driven subway train.